I got my Pandora in late August, and it now has a crack wider than most of the normal seams, spanning between the USB port and the inset video/audio port. I've only plugged into the USB port maybe twice ever, never opened the case, and am very careful with my electronic devices. I haven't tried loosening the screw yet, but the crack seems wide enough that loosening it may have little effect. The plastic bridging between the crack and the normal seam hasn't fallen out yet, thankfully. It doesn't affect usability, at least.
However, I got mine relatively recently in their build process. Perhaps I got an enthusiastic screw-tightening builder...?
I will likely hold onto mine as is unless the crack gets worse, or the nubs start acting up again. I think something had been bound up in them before, and they've been good since whatever might have worked its way out.